Oil paint is a thick material that gives a painted canvas a rough, uneven texture. Unlike acrylics, oil paint takes several days to dry thoroughly. If you want to take advantage of the high quality and bold colours that oil paints offer, but without the uneven surface, you can create a smooth, even finish by selecting the right brushes, preparing the canvas properly, and knowing how to thin the paint.
Purchase a linen canvas to paint on. Linen has a smoother and finer finish than cotton canvas, although it is more expensive. This helps you get a smoother oil painting.
Stretch the canvas properly. To achieve the smoothest surface, staple the canvas to a square stretcher bar while it is resting on a flat surface. Staple the diagonally opposite corners first, then make sure you pull the material taut when you staple the second pair of corners into place.
Prime the surface of the canvas with gesso. This makes the oil paint less likely to crack, and helps it bond to the canvas more easily. Paint a layer of gesso with a brush onto the canvas, then leave it to dry. Repeat this process until you have added several layers of gesso to the surface.
Obtain the right brushes for painting with oils to get a smooth finish. Buy brushes made from hog's hair, as these achieve a smoother finish than synthetic brushes.
Paint with a flat sable brush. This brush has a horizontal, flat-bristled head that works well with glazing. It is also a suitable option for creating a smooth oil painting finish. A Filbert also achieves a smooth finish, as the rounded head allows the paint to be fluidly applied to the canvas.
Loosen the paint with turpentine or linseed oil on a pear-wood palette. Do this by mixing a drop of the turpentine with a bead of oil paint on the palette. The thinner the paint becomes, the smoother finish it will give as it is thinner and easier to apply. You could also substitute turpentine for linseed oil.